1. Field of the Invention
The invention relates to a fabrication of a zeolite thin film, and more particularly, to a fabrication of a zeolite composite film having a regular macroporous-mesoporous-microporous structure.
2. Description of Related Art
The main fabrications of a zeolite thin film are generally secondary growth and spin coating, wherein the template needs to be removed after the fabrication of the thin film. Currently, the most common and easiest fabrication is to use high-temperature calcination to remove the template. However, since the substrate has a different material and a different coefficient of thermal expansion, during calcination, the thin film often ruptures or separates from the substrate. Therefore, current techniques have developed many various fabrications such as solvent extraction, the microwave method, UV decomposition, and ozone oxidation to remove the template and to reduce occurrences of thin film rupture or the thin film separating from the substrate. However, the fabrications usually involve solvents or are very energy consuming, and therefore are not green processes.
To overcome the various problems of the fabrication of a zeolite thin film, the inventor of the present case has previously proposed an aerosol deposition system to fabricate a nanoscale pure silicon MCM-41 thin film (U.S. patent application Ser. No. 13/337,328), wherein during coating, the templating agents in the MCM-41 particles may be removed, eliminating the need for a high temperature calcination process over a long period of time to remove the templating agents. However, the roughness of an ordinary thin film composed of only crystalline particles, as well as the adhesion between the thin film and the substrate, are far worse than the adhesion and the roughness of a thin film composed of colloids such as macromolecules. Therefore, even though the zeolite film has good mechanical strength, hydrothermal stability, and high porosity, in order to enter the commercialization stage, the problems mentioned previously have to be effectively solved.
Based on the above, fabricating a zeolite thin film having higher adhesion and low roughness using a more green fabrication to is a key issue to which a solution is currently needed.